Extracellular Vesicle-Mediated In Vitro Transcribed mRNA Delivery for Treatment of HER2+ Breast Cancer Xenografts in Mice by Prodrug CB1954 without General Toxicity.

Prodrugs are harmless until activated by a bacterial or viral gene product; they constitute the basis of gene-delivered prodrug therapies called GDEPT, which can kill tumors without major side effects. Previously, we utilized the prodrug CNOB (C16H7CIN2O4; not clinically tested) and enzyme HChrR6 in GDEPT to generate the drug MCHB (C16H9CIN2O2) in tumors. Extracellular vesicles (EVs) were used for directed gene delivery and HChrR6 mRNA as gene. Here, the clinical transfer of this approach is enhanced by: (i) use of CB1954 (tretazicar) for which safe human dose is established; HChrR6 can activate this prodrug. (ii) EVs delivered in vitro transcribed (IVT) HChrR6 mRNA, eliminating the potentially harmful plasmid transfection of EV producer cells we utilized previously; this has not been done before. IVT mRNA loading of EVs required several steps. Naked mRNA being unstable, we ensured its prodrug activating functionality at each step. This was not possible using tretazicar itself; we relied instead on HChrR6's ability to convert CNOB into MCHB, whose fluorescence is easily visualizable. HChrR6 mRNA-translated product's ability to generate fluorescence from CNOB vicariously indicated its competence for tretazicar activation. (iii) Systemic IVT mRNA-loaded EVs displaying an anti-HER2 single-chain variable fragment ("IVT EXO-DEPTs") and tretazicar caused growth arrest of human HER2+ breast cancer xenografts in athymic mice. As this occurred without injury to other tissues, absence of off-target mRNA delivery is strongly indicated. Many cancer sites are not amenable for direct gene injection, but current GDEPTs require this. In circumventing this need, a major advance in GDEPT applicability has been accomplished.

EcAMSat spaceflight measurements of the role of σs in antibiotic resistance of stationary phase Escherichia coli in microgravity.

We report the results of the EcAMSat (Escherichia coli Antimicrobial Satellite) autonomous space flight experiment, investigating the role of σs in the development of antibiotic resistance in uropathogenic E. coli (UPEC) in microgravity (µ-g). The presence of σs, encoded by the rpoS gene, has been shown to increase antibiotic resistance in Earth gravity, but it was unknown if this effect occurs in µ-g. Two strains, wildtype (WT) UPEC and its isogenic ΔrpoS mutant, were grown to stationary phase aboard EcAMSat, an 11-kg small satellite, and in a parallel ground-based control experiment; cell growth rates for the two strains were found to be unaltered by µ-g. After starvation for over 24 h, stationary-phase cells were incubated with three doses of gentamicin (Gm), a common treatment for urinary tract infections (which have been reported in astronauts). Cellular metabolic activity was measured optically using the redox-based indicator alamarBlue (aB): both strains exhibited slower metabolism in µ-g, consistent with results from previous smallsat missions. The results also showed that µ-g did not enhance UPEC resistance to Gm; in fact, both strains were more susceptible to Gm in µ-g. It was also found, via a second ground-control experiment, that multi-week storage in the payload hardware stressed the cells, potentially obscuring small differential effects of the antibiotic between WT and mutant and/or between µ-g and ground. Overall, results showed that the ∆rpoS mutant was 34-37% less metabolically active than the WT for four different sets of conditions: ground without Gm, ground with Gm; µ-g without Gm, µ-g with Gm. We conclude therefore that the rpoS gene and its downstream products are important therapeutic targets for treating bacterial infections in space, much as they are on the ground.

Pre-S/Surface and Core Promoter/Precore Mutations in Chronic Hepatitis B Patients with Severe Acute Exacerbation.

BACKGROUND: The role of pre-S/surface and basal core promoter/precore (BCP/PC) mutations in chronic hepatitis B (CHB) patients with severe acute exacerbation (SAE) remains unclear. AIMS: To investigate the role of pre-S/surface and BCP/PC mutations in CHB patients with SAE and mortality. METHODS: A total of 114 CHB patients with spontaneous SAE [alanine aminotransferase (ALT) ≥ 400 U/L] and hepatic decompensation were analyzed along with 114 patients with moderate liver inflammation (ALT: 80-400 U/L without hepatic decompensation) who were matched with the SAE patients in regard to age, sex, HBeAg, and cirrhosis. RESULTS: Compared with patients with moderate liver inflammation, those with SAE had a higher rate of genotype B. Multivariate analysis showed that the independent factors for SAE were V14G/A and L21S in surface genes, codons 109-119 deletions in pre-S1 genes, M1V/T/I in pre-S2 genes, and C1766T/T1768A and C1913A/G mutations in BCP/PC genes. However, these gene variants or mutations were not significant predictors of mortality in patients with SAE. Of the 114 SAE patients, 17 died at week 24 of nucleoside analog treatment. Cox regression analysis showed that independent predictors for mortality at week 24 of treatment in SAE patients were higher international normalized ratio, the presence of ascites, and T1753C/A/G mutations. The SAE patients with T1753C/A/G mutations had a higher rate of acute-on-chronic liver failure (P = 0.006) and higher MELD score (P = 0.018) than those without T1753C/A/G mutations. CONCLUSIONS: The variants or mutations in pre-S/surface and BCP/PC regions might play important roles and could predict mortality in SAE patients.

Anti-HER2 scFv-Directed Extracellular Vesicle-Mediated mRNA-Based Gene Delivery Inhibits Growth of HER2-Positive Human Breast Tumor Xenografts by Prodrug Activation.

This paper deals with specific targeting of the prodrug/enzyme regimen, CNOB/HChrR6, to treat a serious disease, namely HER2+ human breast cancer with minimal off-target toxicity. HChrR6 is an improved bacterial enzyme that converts CNOB into the cytotoxic drug MCHB. Extracellular vesicles (EV) were used for mRNA-based HchrR6 gene delivery: EVs may cause minimal immune rejection, and mRNA may be superior to DNA for gene delivery. To confine HChrR6 generation and CNOB activation to the cancer, the EVHB chimeric protein was constructed. It contains high-affinity anti-HER2 scFv antibody (ML39) and is capable of latching on to EV surface. Cells transfected with EVHB-encoding plasmid generated EVs displaying this protein ("directed EVs"). Transfection of a separate batch of cells with the new plasmid, XPort/HChrR6, generated EVs containing HChrR6 mRNA; incubation with pure EVHB enabled these to target the HER2 receptor, generating "EXO-DEPT" EVs. EXO-DEPT treatment specifically enabled HER2-overexpressing BT474 cells to convert CNOB into MCHB in actinomycin D-independent manner, showing successful and specific delivery of HChrR6 mRNA. EXO-DEPTs-but not undirected EVs-plus CNOB caused near-complete growth arrest of orthotopic BT474 xenografts in vivo, demonstrating for the first time EV-mediated delivery of functional exogenous mRNA to tumors. EXO-DEPTs may be generated from patients' own dendritic cells to evade immune rejection, and without plasmids and their potentially harmful genetic material, raising the prospect of clinical use of this regimen. This approach can be used to treat any disease overexpressing a specific marker. Mol Cancer Ther; 17(5); 1133-42. ©2018 AACR.

Incidence and predictors of HBV relapse after cessation of nucleoside analogues in HBeAg-negative patients with HBsAg ≤ 200 IU/mL.

The predictors of hepatitis B virus (HBV) relapse and HBsAg loss after cessation of nucleos(t)ide analogues (NA) in HBeAg-negative patients with end-of-treatment HBsAg ≤ 200 IU/mL remains unclear. The study recruited 119 chronic hepatitis B (CHB) patients who achieved end-of-treatment HBsAg ≤ 200 IU/mL, were treated with lamivudine (n = 34) and entecavir (n = 85). The 5-year rates of post-treatment virological relapse, clinical relapse, and HBsAg loss at 60 months were 39.4%, 27.6%, and 45.9%, respectively. Cox regression analysis revealed that HBV DNA at entry and end-of-treatment HBsAg levels were independent predictors of virolgical and clinical relapse. HBV genotype C and end-of-treatment HBsAg were independent factors of HBsAg loss. Patients with a combination of end-of-treatment HBsAg < 50 IU/mL and HBV DNA < 2 × 105 IU/mL at entry experienced the lowest virological and clinical relapse rates (5% and 0% at 60 months, respectively). In contract, patients with a combination of end-of-treatment HBsAg ≥ 50 IU/mL and HBV DNA ≥ 2 × 105 IU/mL at entry experienced high virological and clinical relapse (80.7% and 71.5% at 60 months, respectively). No patients experienced hepatic decompensation when clinical relapse occurred after timely retreatment. A combination of HBV DNA levels at entry and end-of-treatment HBsAg levels was useful for predicting the post-treatment HBV relapse in HBeAg-negative patients with HBsAg ≤ 200 IU/mL.

Utilizing native fluorescence imaging, modeling and simulation to examine pharmacokinetics and therapeutic regimen of a novel anticancer prodrug.

BACKGROUND: Success of cancer prodrugs relying on a foreign gene requires specific delivery of the gene to the cancer, and improvements such as higher level gene transfer and expression. Attaining these objectives will be facilitated in preclinical studies using our newly discovered CNOB-GDEPT, consisting of the produrg: 6-chloro-9-nitro-5-oxo-5H-benzo-(a)-phenoxazine (CNOB) and its activating enzyme ChrR6, which generates the cytotoxic product 9-amino-6-chloro-5H-benzo[a]phenoxazine-5-one (MCHB). MCHB is fluorescent and can be noninvasively imaged in mice, and here we investigated whether MCHB fluorescence quantitatively reflects its concentration, as this would enhance its reporter value in further development of the CNOB-GDEPT therapeutic regimen. PK parameters were estimated and used to predict more effective CNOB administration schedules. METHODS: CNOB (3.3 mg/kg) was injected iv in mice implanted with humanized ChrR6 (HChrR6)-expressing 4T1 tumors. Fluorescence was imaged in live mice using IVIS Spectrum, and quantified by Living Image 3.2 software. MCHB and CNOB were quantified also by LC/MS/MS analysis. We used non-compartmental model to estimate PK parameters. Phoenix WinNonlin software was used for simulations to predict a more effective CNOB dosage regimen. RESULTS: CNOB administration significantly prolonged mice survival. MCHB fluorescence quantitatively reflected its exposure levels to the tumor and the plasma, as verified by LC/MS/MS analysis at various time points, including at a low concentration of 2 ng/g tumor. The LC/MS/MS data were used to estimate peak plasma concentrations, exposure (AUC0-24), volume of distribution, clearance and half-life in plasma and the tumor. Simulations suggested that the CNOB-GDEPT can be a successful therapy without large increases in the prodrug dosage. CONCLUSION: MCHB fluorescence quantifies this drug, and CNOB can be effective at relatively low doses. MCHB fluorescence characteristics will expedite further development of CNOB-GDEPT by, for example, facilitating specific gene delivery to the tumor, its prolonged expression, as well as other attributes necessary for successful gene-delivered enzyme prodrug therapy.

Sigma S-dependent antioxidant defense protects stationary-phase Escherichia coli against the bactericidal antibiotic gentamicin.

Stationary-phase bacteria are important in disease. The σ(s)-regulated general stress response helps them become resistant to disinfectants, but the role of σ(s) in bacterial antibiotic resistance has not been elucidated. Loss of σ(s) rendered stationary-phase Escherichia coli more sensitive to the bactericidal antibiotic gentamicin (Gm), and proteomic analysis suggested involvement of a weakened antioxidant defense. Use of the psfiA genetic reporter, 3'-(p-hydroxyphenyl) fluorescein (HPF) dye, and Amplex Red showed that Gm generated more reactive oxygen species (ROS) in the mutant. HPF measurements can be distorted by cell elongation, but Gm did not affect stationary-phase cell dimensions. Coadministration of the antioxidant N-acetyl cysteine (NAC) decreased drug lethality particularly in the mutant, as did Gm treatment under anaerobic conditions that prevent ROS formation. Greater oxidative stress, due to insufficient quenching of endogenous ROS and/or respiration-linked electron leakage, therefore contributed to the greater sensitivity of the mutant; infection by a uropathogenic strain in mice showed this to be the case also in vivo. Disruption of antioxidant defense by eliminating the quencher proteins, SodA/SodB and KatE/SodA, or the pentose phosphate pathway proteins, Zwf/Gnd and TalA, which provide NADPH for ROS decomposition, also generated greater oxidative stress and killing by Gm. Thus, besides its established mode of action, Gm also kills stationary-phase bacteria by generating oxidative stress, and targeting the antioxidant defense of E. coli can enhance its efficacy. Relevant aspects of the current controversy on the role of ROS in killing by bactericidal drugs of exponential-phase bacteria, which represent a different physiological state, are discussed.

The effect of systemic antibiotic prophylaxis for cirrhotic patients with peptic ulcer bleeding after endoscopic interventions.

PURPOSE: All previous studies reported the benefit of antibiotic prophylaxis in cirrhotic patients with either a mixture of nonvariceal and variceal bleeding or variceal bleeding alone. Reports on sole peptic ulcers bleeding are lacking. We aimed to assess the effect of antibiotic prophylaxis in cirrhotic patients with peptic ulcer bleeding after endoscopic interventions and the risk factors associated with recurrent bleeding. METHODS: A cross-sectional retrospective chart review study was conducted on 148 cirrhotic patients with acute peptic ulcer hemorrhage who underwent therapeutic endoscopic procedures. Patients who received prophylactic intravenous ceftriaxone were classified as group A (n = 38) and those who did not receive antibiotics were classified as group B (n = 110). The outcomes were prevention of infection, length of hospital stay, time of rebleeding, and death. RESULTS: More patients suffered from recurrent bleeding and infection in group B than those in group A (28.2 vs. 5.3 %; p = 0.003, and 26.4 vs. 10.5 %; p = 0.043, respectively). The risk factors associated with recurrent bleeding were being male (OR = 3.4; p = 0.024), those with advanced stage of cirrhosis with Child-Pugh's class C (OR = 3.8; p < 0.001), and those without antibiotic prophylaxis (OR = 8.9; p = 0.003). The observed 30-day survival was virtually identical for both groups (p = 0.279). CONCLUSIONS: Antibiotic prophylaxis in cirrhotic patients after endoscopic interventions for acute peptic ulcer hemorrhage reduced infections and decreased rebleeding. Male gender, cirrhosis Child-Pugh's class C, and no antibiotic prophylaxis were independent predictors of recurrent bleeding. Further studies should be directed to explore ways to improve the overall outcome of these patients.

Effect of endotoxin on the expression of placental drug transporters and glyburide disposition in pregnant rats.

On average, 80% of pregnant women consume over-the-counter and/or prescription medications. The placenta is a crucial organ that can restrict fetal drug exposure. ATP-binding cassette (ABC) drug transporters play an important role in the placenta because they limit the transplacental transfer of xenobiotics. However, the impact of infection or inflammation on placental drug transporters is not well established. Thus, we examined the impact of endotox-in-induced inflammation on the placental expression of several key drug transporters in rats and its impact on fetal exposure to a drug substrate. Real-time polymerase chain reaction results demonstrated a significant time- and dose-dependent down-regulation of breast cancer resistance protein/Abcg2 mRNA in the placentas of endotoxin-treated rats with a corresponding decrease in protein levels. Likewise, the mRNA levels of several other ABC transporters (Abcb1a, Abcb1b, Abcc1, Abcc2, Abcc3) and members of the organic anion-transporting polypeptides (Slco1a4, Slco2b1, Slco4a1) were down-regulated. A biodistribution study was carried out with glyburide, a hypoglycemic sulfonylurea substrate of both ABC efflux and Oatp uptake transporters. Although administration of endotoxin resulted in comparable plasma concentrations of glyburide, a pronounced increase in the accumulation of glyburide was seen in the fetuses of endotoxin-treated rats (162% of controls, p < 0.01). Glyburide plasma protein binding was not affected by endotoxin treatment. Overall, our results demonstrated a significant reduction in the placental expression of several important drug transporters during endotoxin-induced inflammation. Alterations in glyburide distribution highlight the potential importance of both influx and efflux placental transporters in impacting fetal drug exposure.

Amyloid beta peptide and NMDA induce ROS from NADPH oxidase and AA release from cytosolic phospholipase A2 in cortical neurons.

Increase in oxidative stress has been postulated to play an important role in the pathogenesis of a number of neurodegenerative diseases including Alzheimer's disease. There is evidence for involvement of amyloid-beta peptide (Abeta) in mediating the oxidative damage to neurons. Despite yet unknown mechanism, Abeta appears to exert action on the ionotropic glutamate receptors, especially the N-methyl-D-aspartic acid (NMDA) receptor subtypes. In this study, we showed that NMDA and oligomeric Abeta(1-42) could induce reactive oxygen species (ROS) production from cortical neurons through activation of NADPH oxidase. ROS derived from NADPH oxidase led to activation of extracellular signal-regulated kinase 1/2, phosphorylation of cytosolic phospholipase A(2)alpha (cPLA(2)alpha), and arachidonic acid (AA) release. In addition, Abeta(1-42)-induced AA release was inhibited by d(-)-2-amino-5-phosphonopentanoic acid and memantine, two different NMDA receptor antagonists, suggesting action of Abeta through the NMDA receptor. Besides serving as a precursor for eicosanoids, AA is also regarded as a retrograde messenger and plays a role in modulating synaptic plasticity. Other phospholipase A(2) products such as lysophospholipids can perturb membrane phospholipids. These results suggest an oxidative-degradative mechanism for oligomeric Abeta(1-42) to induce ROS production and stimulate AA release through the NMDA receptors. This novel mechanism may contribute to the oxidative stress hypothesis and synaptic failure that underline the pathogenesis of Alzheimer's disease.

99mTc-Sestamibi, a sensitive probe for in vivo imaging of P-glycoprotein inhibition by modulators and mdr1 antisense oligodeoxynucleotides.

PURPOSE: We tested the suitability of (99m)Tc-sestamibi to image the inhibition of P-glycoprotein (Pgp)-mediated multidrug resistance in tumor cells and xenografts after antisense treatment and/or inhibition with a novel Pgp modulator WK-X-34. PROCEDURE: Pgp inhibition was measured by daunorubicin transport assays and fluorescence microscopy in resistant A2780/Adr cells treated with WK-X-34 and antisense. A2780/Adr xenograft mice were dosed with mdr1 antisense oligodeoxynucleotides intratumorally for three days; next, mice were treated with WK-X-34, followed by (99m)Tc-sestamibi injection. Mice were imaged, sacrificed, and tissues collected. Images and isolated tissues were analyzed for (99)Tc distribution. Pgp expression was analyzed by immunofluorescence and reverse transcription-polymerase chain reaction. RESULTS: Both WK-X-34 and mdr1 antisense treatments significantly inhibited Pgp activity in vitro and in xenografts. Biodistribution results correlated with results from the (99m)Tc-sestamibi images. Mdr1 mRNA and Pgp were significantly down-regulated by antisense treatments. CONCLUSIONS: (99m)Tc-sestamibi is a sensitive probe to monitor Pgp inhibition by different mechanisms in vivo in tumor xenografts.

Detection of P-glycoprotein activity in endotoxemic rats by 99mTc-sestamibi imaging.

UNLABELLED: (99m)Tc-sestamibi is a widely used radiopharmaceutical agent for myocardial and oncologic imaging. Because of its unique role as a P-glycoprotein (Pgp)-specific substrate, this compound can be used to examine Pgp functional activity in vitro and in vivo under pathologic conditions. Our objective was to use (99m)Tc-sestamibi as a tool to investigate whether systemic inflammation induced by Escherichia coli lipopolysaccharide (LPS) would affect in vivo Pgp function in the brain, heart, liver, and kidneys of rats. Moreover, we also wanted to examine LPS-mediated effects in the placenta of pregnant rats because of the limited amount of in vivo data on this tissue. METHODS: Rats were injected intraperitoneally with LPS or an equal volume of saline as controls. After certain time periods (6 or 24 h), animals were administered 20 MBq of (99m)Tc-sestamibi intravenously, and then images were taken at 0.5, 1, 2, and 3 h. Tissues of rats were excised for (99m)Tc-sestamibi biodistribution analysis by gamma-counting and messenger RNA (mRNA) analysis by reverse transcription-polymerase chain reaction. Western blot analysis with antibody C-219 was used to detect Pgp levels. RESULTS: LPS treatment for 6 h caused a significant downregulation of mdr1a mRNA levels in the brain, heart, and liver, whereas 24 h of LPS treatment significantly reduced mdr1a mRNA levels only in the liver. A significant downregulation of mdr1a mRNA was seen in the brain, heart, and liver within 6 h after LPS administration. Imaging and biodistribution studies demonstrated a higher accumulation of (99m)Tc-sestamibi in the brain, heart, and liver of LPS-treated rats. In the brain, LPS-imposed downregulation of mdr1a mRNA levels was transient, with significant suppression at 4, 6, and 12 h, and the levels recovered to nearly normal by 24 h. This time-dependent downregulation of mRNA correlated with protein levels determined by Western blot analysis. Biodistribution studies of pregnant rats demonstrated a 3.5-fold-higher accumulation of (99m)Tc-sestamibi in the fetal tissues of LPS-treated pregnant rats than in saline-treated control rats. Furthermore, placental mdr1a and mdr1b mRNA levels were also significantly downregulated by LPS treatment. CONCLUSION: Our results indicate that LPS-induced systemic inflammation caused an increased retention of (99m)Tc-sestamibi in the brain, heart, liver, and fetal tissues. These results correlated with a reduction in mdr1a mRNA levels in each organ.